How to join two images into one with FFmpeg?

Question

There are two images: a.jpg and b.jpg.

I just want to know how to join them into one image using ffmpeg.

How should I finish the ffmpeg -i a.jpg -i b.jpg command to get a c.jpg output image?

This is an example of what I am trying to achieve:

1. a.jpg

   

2. b.jpg

   

3. c.jpg

   

Answer 1

Use the hstack filter.

2 images:

ffmpeg -i a.jpg -i b.jpg -filter_complex hstack output.jpg

3 images:

ffmpeg -i a.jpg -i b.jpg -i c.jpg -filter_complex "[0][1][2]hstack=inputs=3" output.jpg

• If you want to vertically stack use vstack instead.
• See Vertically or horizontally stack several videos using ffmpeg? for more examples.
• To change quality see How can I output a good quality JPEG image from ffmpeg?